Accumulators are employed as a network-independent electric power supply in a variety of portable and stationary devices. In devices with a high energy demand, including, for example, hearing aids, drug dispensers and/or diagnostic devices, primary cells can also be employed, although these have the disadvantage that, conversely to accumulators, these are not rechargeable, and must be replaced every five to ten days.
From DE 10 2009 060 800 A1 (VARTA, 2011), button cells with wound electrodes and cup-shaped metal housings for accumulators and non-rechargeable batteries are known. In practice, button cells of this type are employed for structural heights in excess of 5 mm. For smaller structural heights, the wound design is disadvantageous, on the grounds of the excessively small active volume. Button cells with a metal housing are, moreover, restricted in their shape. In turn, this prevents the optimum exploitation of an available volume in a device which is to be operated by a button cell and, in consequence, reduces the capacity of the button cell.
US 20140072860 A1 (SWISSBAT, 2014) discloses an accumulator with a plastic housing and a stacked electrode design. The conductor tabs of the anode and cathode are respectively positioned on a metal block and welded together. The relatively large space requirement for the conductor block and the conductor tabs is disadvantageous. Consequently, this design is largely unsuitable for accumulators of a small size or the smallest size such as, for example, button cells. Moreover, automatic stacking of the electrodes, on the grounds of the different lengths and different angles of the conductor tabs, is a very difficult and expensive process.
From EP 1 100 138 A (Wyon A G, 2001), an accumulator is known of a space-saving and customized design, having wound electrodes, integrated protective and charging circuitry and a plastic housing, in order to permit the replacement of conventional zinc-air primary cells in fields of application with a high energy demand including, for example, auditory implants. The current terminal is of tubular design, the abutment of which against the housing base is associated with a loss of space. Moreover, electrical contacting by means of pins which project into the housing is not suitable for devices, the batteries of which require frequent replacement.
U.S. Pat. No. 7,294,430 B2 (Wyon A G, 2007) therefore proposes a mechanically-tensionable connection and a contact terminal on the outer side of the housing, in the interests of straightforward contacting with a device. However, this form of construction is unsuitable for accumulators with wound electrodes and a structural height of less than 6 mm, on the grounds of the relatively small active volume.
In order to achieve a space-saving arrangement of electrodes in button cells, with a simultaneously high efficiency, U.S. Pat. No. 8,685,560 (Wyon, 2014) proposes folded electrodes in a metal housing.